6 pellets in the "kill zone", which I presume means the brain and spine, is not overly impressive for a 3", 2oz load. With those results I would say your reasonable limit in the field is 30 yards. For years I shot 3" Federals or Winchesters, 2oz of #5s, in aRemingoton870 using the Remingtonextra full extended choke. That combo killed turkeys cleanly at ranges up to 50 yards, and I only used the small bead sight thatcame on the gun. I liked it because it was small and I could precisely aim the gun, even at longer ranges - in other words it didn't obscure the target at longer ranges.

I would suggest the following:

Go out and shoot the gun again using a good solid rest to steady your aim. If the point of impact (center of the pattern) is not where you are aiming then you will need to either adjust your hold (aim) or install some adjustable sights. I don't like to adjust aim. I want the gun shooting where I aim it, so the adjustable sights might be the way to go.

If your aim is good and the center of the pattern is roughly between the turkey's waddles and the top if his head, and you are only putting 6 shots in the "kill zone" at 30 yards, then it is time to look atchanging ammo or choke. I think it is easier to try different ammo, and you can likely find some that shoots well with your gun and choke. My best results are with Hevi-13; your results may vary. I was able get 47 pellets in the head and neck from 35 yards shooting 1.75 oz of Hevi-13 #6 out of a Mossberg 835 (3.5 inch, but the 3" load contains the same 1.75 oz of shot). The turkey I shot Sunday at 27 yards was knocked off his feet, and when I got to him there was blood pouring from his head.

good luck

Mouthcaller